Development of food aversions during illness.

Food aversions, particularly those which are acquired as a result of unpleasant experiences with foods, represent a potent defence mechanism against poisoning. Humans, as well as a broad range of animal species, appear strongly predisposed to associate certain symptoms of discomfort with foods they have eaten and to subsequently dislike and avoid those foods. Although food aversion learning serves a clearly adaptive function in certain circumstances, there appear to be other situations, such as chronic illness, in which food aversions arise and have deleterious effects on nutritional status and general health. The present article will review the basic research literature on food aversion learning and then go on to a discussion of evidence that chronic illness can be associated with the development of food aversions, and that such aversions can affect food intake and body weight. Although many of these studies were done in rats, evidence for comparable processes in humans will be included when available.